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Yamaha Fuel Management Gauges
"Short Wave Sportfishing" wrote in message ... On Fri, 04 Jul 2008 10:12:05 -0400, HK wrote: Short Wave Sportfishing wrote: On Fri, 04 Jul 2008 08:25:15 -0400, Gene Kearns wrote: On Fri, 4 Jul 2008 06:29:26 -0400, Jim penned the following well considered thoughts to the readers of rec.boats: "Graham" wrote in message news:ypjbk.54744$Jx.31786@pd7urf1no... Does anyone know if these gauges display miles per gallon (or litres per km) or just miles travelled and gallons consumed? Do they need any special interface to work with standard GPS's like a Raytheon chart plotter? Thanks, Graham The GPS reports miles per hour over land. It would be useless to use those calculations in determining real miles per gallon over the surface of the water. Au contraire, mon ami! The Yamaha fuel management gages must receive a fuel flow and GPS (or speedometer... IMHO,useless) input. You must provide the GPS. I'm not sure what format(s) of in/output are acceptable, but I suspect it is configurable to standard formats IOW.... I don't think any special interface is necessary (since you are likely using the Command Link interface, already), if the GPS unit outputs a format recognizable to the FMM.. http://www.yamaha-motor.com/outboard...nk/page05.aspx No, I think Jim is right. The link doesn't really give you any information on what data sets are actually being shared and what format - I would assume NEMA 183.X which is the defacto standard. The major issue would be connectors on that harness they supply and how compatiable it is with other units. However, being NEMA 183 systems, the connector to the hub has to be something standard - maybe like a N connector or RCA jack. To the point though, what purpose would having a fuel flow meter do a calculation based on GPS? The calculation would be simpler and more efficient to take the fuel flow data in GPH and base the rest of the calculation on that - position has nothing to do with fuel usage. GPH has a direct correlation to RPM and MPG - why complicate things? For instance, if the metering system does the calculations and you select MPG, then you know if you are using more or less fuel to reach your destination - X miles equals Y fuel (or the inverse - Y fuel equals X miles). Same with GPH - X miles equals Y operating time equals Z available miles. GPS has nothing to do with fuel usage. Well, this has been a fun read so far. There are *two* different Yamaha gauges available that display fuel usage. One is a fuel management meter unit. The other is a speed and fuel meter unit. Interestingly, the "speed sensor" on the engine is incredibly accurate, at least it is on my boat. It gives just about the same reading as the GPS at all times that I have noticed. The fuel management meter shows flow, fuel available, total consumption, and miles or nautical miles per gallon. Metric read-outs are also available. The speed and fuel meter unit does not display the amount of fuel available. But it does have functions not available on the fuel management meter. That's similar to the unit I have with the ETEC. I have the Command Link Multifunction Meter Installation Manual somewhere. I'd be curious what the data format is and what version. Still doens't answer the question though - why bother with hooking a GPS into the system? Speed over ground and speed in water will average out to about the same in a day of running. Sometimes with the current and others against the current. And how many people in lakes and ocean are running against large currents for a long time? |
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